Passive sampling of PAHs in indoor air in Nepal

PAHs were sampled in ten homes in the Makwanpur region, Nepal. SPMDs and moss bags (Sphagnum girgensohnii) were used as passive samplers. Soot particles on the SPMD surfaces were also analyzed for PAHs. The overall PAH concentrations in SPMDs were significantly higher than those in moss bags. Total PAH mean concentrations of ten houses were 535μg/g lipid for SPMDs and 7.2 μg/g moss (dw) for moss bags. Ratios of phenanthrene/anthracene in indoor SPMDs and particulate matter varied from 2.9 to 3.5 and ratios of fluoranthene/pyrene varied from 1.1 to 1.4. The values for moss bags were respectively 1.7–3.6 and 0.8–2.4. These ratios indicate that the PAHs are from combustion origin. The PAH concentrations in ambient air were estimated as B(a)P TEQs and they were 17–64 times higher than acceptable limit for Finnish community air. Based on PAH levels in the gas phase (SPMD) we may expect PAHs to have an impact on respiratory disease prevalence in Nepalese villages. Both of the sampling methods were feasible in the difficult conditions under which the study was performed.     

Comparison of first-order-decay modeled and actual field measured municipal solid waste landfill methane data

The first-order decay (FOD) model is widely used to estimate landfill gas generation for emissions inventories, life cycle assessments, and regulation. The FOD model has inherent uncertainty due to underlying uncertainty in model parameters and a lack of opportunities to validate it with complete field-scale landfill data sets. The objectives of this paper were to estimate methane generation, fugitive methane emissions, and aggregated collection efficiency for landfills through a mass balance approach using the FOD model for gas generation coupled with literature values for cover-specific collection efficiency and methane oxidation. This study is unique and valuable because actual field data were used in comparison with modeled data. The magnitude and variation of emissions were estimated for three landfills using site-specific model parameters and gas collection data, and compared to vertical radial plume mapping emissions measurements. For the three landfills, the modeling approach slightly under-predicted measured emissions and over-estimated aggregated collection efficiency, but the two approaches yielded statistically equivalent uncertainties expressed as coefficients of variation. Sources of uncertainty include challenges in large-scale field measurement of emissions and spatial and temporal fluctuations in methane flow balance components (generated, collected, oxidized, and emitted methane). Additional publication of sets of field-scale measurement data and methane flow balance components will reduce the uncertainty in future estimates of fugitive emissions.     

Chemical sequential extraction of heavy metals and sulphur in bottom ash and in fly ash from a pulp and paper mill complex

A five-stage sequential extraction procedure was used to determine the distribution of 11 metals (Cd, Cr, Cu, Mo, Pb, Zn, As, Co, V, Ni, Ba), and sulphur (S) in bottom ash and in fly ash from a fluidized bed co-combustion (i.e. wood and peat) boiler of Stora Enso Oyj Oulu Mill at Oulu, Northern Finland, into the following fractions: (1) water-soluble fraction (H2O); (2) exchangeable fraction (CH3COOH); (3) easily reduced fraction (NH2OH-HCl); (4) oxidizable fraction (H2O2 + CH3COONH4); and (5) residual fraction (HF + HNO3 + HCl). Although metals were extractable in all fractions, the highest concentrations of most of the metals occurred in the residual fraction. From the environmental point of view, this fraction is the non-mobile fraction and is potentially the least harmful. The Ca concentrations of 29.3 g kg(-1) (dry weight) in bottom ash and of 68.5 g kg(-1) (dry weight) in fly ash were correspondingly approximately 18 and 43 times higher than the average value of 1.6 g kg(-1) (dry weight) in arable land in Central Finland. The ashes were strongly alkaline pH (approximately 12) and had a liming effects of 9.3% (bottom ash) and 13% (fly ash) expressed as Ca equivalents (dry weight). The elevated Ca concentrations indicate that the ashes are potential agents for soil remediation and for improving soil fertility. The pH and liming effect values indicate that the ashes also have a pH buffering capacity. From the environmental point of view, it is notable that the heavy metal concentrations in both types of ash were lower than the Finnish criteria for ash utilization.     

Safety compliance climate concerning risk assessment and preventive measures in EU legislation: A Finnish survey

The aim of the present study is to explore the process dynamics of the safety compliance climate and work relationships, including their antecedents and consequences. After investigating the many dimensions of safety compliance climate and of work relationships, the study concludes that a multi-component measure is needed to fully assess all of their dimensions. With respect to the impacting positively on safety compliance legislation, the present study found the following factors: “contribution measures”, “concrete preventive measures” and “risk assessment process”. For risk assessment factors on safety compliance the study identified “planning, guidelines, policy, management”, “prioritization of proactive measures”, “results in cooperation and information” and “active use of risks assessment document”. In a regression model for the workers, both risk assessment process and contribution measures had a statistically highly significant (p < 0.001) effect on concrete preventive measures. In the regression analysis of the employers risk assessment process had a statistically significant (p < 0.01) effect and contribution measures had a statistically highly significant (p < 0.001) effect on concrete preventive measures.